It is the concentration of a few signaling molecules that determines the fate of individual cells during the early development of organisms. In the renowned journal Current Biology, a team of molecular biologists led by Pia Aanstad of the University of Innsbruck reports that a variety of molecular mechanisms accounts for the interpretation of the concentration of the signaling molecule Hedgehog.

The development of an organism is a complex process to which a dozen or hundreds of signaling molecules contribute. Some of these molecules have dozens of functions in the fruit fly and in humans alike. One of these molecules – Hedgehog – controls the development of, for example, the extremities, the central nervous system, the teeth, eyes, hair, lung and the gastrointestinal tract. “What is most remarkable: The cells are told what to do not only because the molecule is present but also by the different concentrations of the molecules in the tissue”, says group leader Pia Aanstad of the Institute for Molecular Biology of the University of Innsbruck. “The concentration of Hedgehog makes the thumb of the right hand grow on the left hand side and the thumb of the left hand grow on the right hand side.” Thus, scientists define Hedgehog as a morphogen – a signal that is concentration-dependent and controls the pattern formation of an organism. A mutation in this signaling pathway induces dramatic and embryonically lethal malformations in the early developmental stage such as the formation of just one central eye. Defects in the Hedgehog signaling pathway in humans are a cause for one of the most common birth defects – holoprosencephaly. “Hedgehog genes are not new in evolution and the signaling pathway functions in the fly, mouse, fish and in humans similarly”, says Pia Aanstad. In her research work she focuses on the zebra danio or zebra fish. Due to the short developmental cycle, the scientists are able to observe the development of the small tropic fish in fast motion. “We want to better understand how the cells process the signals of the signaling molecules and how they react.”

Mutants do not react to high concentrations

Already during her time as a post doc in San Francisco, U.S., Pia Aanstad discovered a mutated zebra fish whose Hedgehog signaling pathway was disrupted. The fish showed a genetic alteration at the so-called Smoothened (Smo) protein, which is located at the cell membrane and transfers the Hedgehog signal into the cell. In 2005, Aanstad and her colleagues published a paper in the renowned journal Nature, in which they showed that Smo is concentrated at cilia (cellular projections) and also functions at the cilium. “By using high-resolution fluorescence microscopy, we have now shown that in the new mutants a small genetic alteration at the extracellular part of this protein inhibits localization in the cilia and that while the cells identify the Hedgehog signals, they interpret the concentration incorrectly”, explains Pia Aanstad. “This is evidence for the notion that cells use various molecular mechanisms for interpreting different Hedgehog concentrations.” This fact may also be of importance for the diagnosis and treatment of certain cancers (basal cell carcinoma), where the constant up-regulation of the Hedgehog signal is responsible for uncontrolled cell growth. Aanstad published the findings together with her colleagues from the University of California, San Francisco in the journal Current Biology.

Source: University of Innsbruck

This press release is also available in German.

COLLEGE STATION – The loss and fragmentation of Texas’ farms, ranches and forests is part of a continued trend that highlights the importance of rural lands in maintaining the state’s natural resources and economic base, according to a newly released study.

The study shows that lands classified as farms, ranches and forests declined in 156 of Texas’s 254 counties between 1997 and 2006. In all, there was a loss of 2.1 million acres of agricultural lands since 1997, the report notes.

“When you talk about the infrastructure of the economy and life in Texas, land is it,’” said Dr. Neal Wilkins, one of the study’s authors and director of the Texas A&M Institute of Renewable Natural Resources.

The study, commissioned by American Farmland Trust, indicated that about 50 percent of the land converted from agriculture to other uses was concentrated in the state’s 50 highest-growth counties. These counties lost 1,084,566 acres while increasing in population by 4,017,765 residents.

“In some regions, including South Texas and the Edwards Plateau, our state’s rural lands continue to be divided into smaller acreages, and this may have consequences for future profitability” Wilkins said. “According to the data, only 50 percent of farms and ranches below 500 acres showed a net profit during 2007. In addition, these fragmented ownerships are more likely to be converted to non-native pastures and become a challenge for managing wildlife and other natural resources.”

While the report showed an increase of about 1,900 new farms and ranches in Texas, he noted, the average size dropped to 527 acres in 2007 from 585 acres 10 years earlier.

“Where traditional agriculture has declined in profitability, landowners have faced a hard decision of having to sell parcels of land,” Wilkins explained. “When that happens, the open land becomes fragmented, and the consequence is the loss of rural lands to support our natural resources.”

American Farmland Trust’s Texas advisor, Blair Fitzsimmons, agreed.

“Agricultural lands provide significant public benefits such as clean, abundant water, carbon sequestration and clean air,” she said. “This study is a wake-up call that those public benefits are disappearing.”

One unique feature of the study, however, is a new tool developed to aid policymakers and local officials in making land-use decisions, Wilkins pointed out.

The Texas Land Trends Web site, http://www.txlandtrends.org/ , links to a trend visualizer – an exhaustive database that enables one to view 10-year land-use trends by Texas county, area (such as I-35 corridor), river basin or ecoregion.

“This is an amazing new way to access information and visualize what it means,” Wilkins said. “It makes the information local and personal.”

Wilkins and his team spent about nine months gathering information from readily available sources — including the U.S. Census, U.S. Department of Agriculture, and the Texas Comptroller of Public Accounts — to access the land use data for over 1,000 school districts, for example. That data was combined with natural resource expertise. Computer programmers and potential user groups assisted in making the Web site easy to navigate.

Among the other overall trends reported in the study:

• Texas now has about 142 million acres of private farms, ranches and forests, equaling 84 percent of the state’s entire land area.
• The state has more than 247,000 farms and ranches.
• The land base for Texas agriculture decreased by as much as 2 percent between 1997 and 2007.
• In high-growth areas, about 270 acres of agricultural land are converted to non-agricultural use for every 1,000 new residents added to the population.
• As of 2007, operations with less than 100 acres occupied about 3 percent of the state’s land but more than 50 percent of the farms and ranches.
• Texas land values increased about 140 percent to an average of $1,196 per acre, though much higher values are found near metropolitan areas.

Wilkins said some of the regions with the fastest losses to fragmentation were in the Trans Pecos, Edwards Plateau and South Texas regions where more than 2.8 million acres were chopped into small- and mid-sized parcels since 1997.

One positive note, however, is in the northern areas of the state where some 2.5 million acres were consolidated into larger operations, he added. For understanding how remaining land is being used, Wilkins pointed out, the online trend visualizer provides data not only on totals but specifically on irrigated cropland, dry cropland, non-native pasture, native rangeland, wildlife management, forests and other uses. Each of these also can be determined by county, area, river basin or ecoregion.

The largest overall land-use category is native rangeland at 92.6 million acres, the report noted.

Another trend is an increase in the use of land for wildlife management which the report indicated resulted from state legislation in 1996 that provided tax appraisal benefits for that category. Wildlife management land use now accounts for 2.37 million acres statewide.

“We hope this tool will be useful in helping people understand the trends in Texas land use and how that will impact society,” Wilkins added.

Source: Texas A&M AgriLife Communications

The powerful Habsburg dynasty ruled Spain and its empire from 1516 to 1700 but when King Charles II died in 1700 without any children from his two marriages, the male line died out and the French Bourbon dynasty came to power in Spain. Reporting in the open-access, peer-reviewed journal PLoS ONE, April 15, Gonzalo Alvarez and colleagues at the University of Santiago de Compostela, Spain, provide genetic evidence to support the historical evidence that the high frequency of inbreeding (mating between closely related individuals) within the dynasty was a major cause for the extinction of its male line.

Using the genealogical information for Charles II and 3,000 of his relatives and ancestors across 16 generations, the researchers calculated the inbreeding coefficient (F) for each individual; this value indicates the probability that an individual receives, at a given locus, two genes identical by descent due to the common ancestry of its parents. They found that F increased considerably down the generations—from 0.025 for Philip I, the founder of the dynasty, to 0.254 for Charles II—as the Habsburg kings tended to marry close relatives more frequently in order to preserve their heritage. Several members of the dynasty had inbreeding coefficients higher than 0.20, which means that more than 20% of the genome is expected to be homozygous in these individuals.

The authors cite three lines of evidence to support the theory that inbreeding was a major factor in the extinction of the male Habsburg line, on the death of Charles II.

Firstly, there was a very high level of marriage between biological relatives (consanguineous marriage) within the Habsburg dynasty: nine of the 11 marriages over 200 years were consanguineous, including two uncle-niece marriages, one double-first-cousin marriage and one first-cousin marriage.

The two individuals with the highest inbreeding coefficient were Charles II and his grandfather Philip III. Although both were the sons of uncle-niece marriages, their F values were almost as high as the expected value for the offspring of an incestuous (parent-child or brother-sister) marriage. The researchers explain that this is likely to be due to multiple remote ancestors of these individuals (remote inbreeding), on top of the high degree of relatedness of their parents.

Secondly, there was a high rate of infant and child mortality in the Habsburg families with only half of the children born in the dynasty during the years studied surviving to age one, compared to about 80% in Spanish villages of the time. Alvarez and colleagues calculated that inbreeding at the level of first cousin (F = 0.0625) exerted an adverse effect on the survival to age 10 of offspring of 17.8 % ± 12.3, which could explain the high levels of infant and child mortality.

Thirdly, Charles II, dubbed El Hechizado (”The Hexed”), suffered from many different disorders and illnesses, some of which may result from the consanguineous marriage of his parents. According to contemporary writings he was short and weak and suffered from intestinal problems and sporadic hematuria. Children of closely consanguineous couples often have an increased incidence of detrimental health effects due to rare deleterious recessive alleles inherited from common ancestors, although this will depend on how inbred their pedigree is already.

Based on this clinical genetic knowledge and on information gathered by historians on the health of Charles II, Alvarez and colleagues speculate that the simultaneous occurrence of two different genetic disorders (combined pituitary hormone deficiency and distal renal tubular acidosis), determined by recessive alleles at two unlinked loci, could explain much of the complex clinical profile of this king, including his impotence/infertility, which led to the extinction of the dynasty.

Source: Public Library of Science

All African Pygmies, inhabiting a large territory extending west-to-east along Central Africa, descend from a unique population who lived around 20,000 years ago, according to an international study led by researchers at the Institut Pasteur in Paris. The research, published April 10 in the open-access journal PLoS Genetics, concludes that the ancestors of present-day African Pygmies and farmers separated ~60,000 years ago.

Pygmies are characterized by a forest-dwelling hunter-gathering lifestyle and distinctive cultural practices and physical traits (e.g., low stature). Two groups of Pygmy populations live in the African rainforests: the “Western Pygmies” and the “Eastern Pygmies”. The common origins of the two groups of Pygmies, separated by thousands of kilometers, have been long debated, and their relationships with neighboring farmers remained obscure.

The researchers, led by Lluis Quintana-Murci, studied the genetic profile of twelve populations of Pygmies and neighboring farmers dispersed over the African continent, using sequence data from non-coding regions of their genomes. Using simulation-based procedures, they determined that the ancestors of Pygmy hunter-gatherers and farming populations started to diverge ~60,000 years ago, coinciding with a period of important human migration both within and outside Africa. Much later, ~20,000 years ago, Western and Eastern Pygmies separated, concurrently with a period of climate change leading to large retreats of the equatorial rainforest into refugia.

The common origin of all Pygmies unmasked in this study led Etienne Patin, one of the leading authors, to conclude that “they have probably inherited their distinctive shared physical traits, such as low height, from a common ancestor, rather than by convergent adaptation to the rainforest”. However, complete genome-wide profiles of these populations are now needed, both to characterize more precisely their demographic history and to identify genes involved in the adaptation of these populations with different lifestyles to their specific ecological habitats.

Source: Public Library of Science

Credit: The American Chemical Society

Adults facing unexpected career changes, take note. Scientists from Brazil and Cuba are reporting that honey bees — a mainstay for behavioral research that cannot be done in other animals — change their brains before transitioning to that new job. Appears in the current edition of ACS’ monthly Journal of Proteome Research, the research provides valuable insight into the biochemistry behind the behavior, feats of navigation, and social organization in these animals.

In the study, Marcelo Valle de Sousa and colleagues point out that worker bees begin adult life by performing tasks in the nest such as brood nursing. By 2-3 weeks of age, however, these females — equivalent to middle age in human years —switch to foraging for nectar and pollen. Foraging requires a new skill set that includes uncanny ability to navigate to and from feeding sites, communicating the location of food to other bees, and flights of hundreds of miles in a lifetime.

The researchers collected and analyzed hundreds of bee brains, comparing the proteins scripted by the genes in nurses and foragers in order to find proteins related to the genetic and behavioral shifts during these career transitions. The brains of nurse bees have higher levels of certain “royal jelly” proteins involved in caste determination. Experienced foragers, in contrast, over expressed proteins linked to energy production and other activities.

“Our study demonstrated clear brain proteome differences between honey bee nurse and forager subcastes with distinct social roles,” the study says. – AD
“Proteomic Analysis of Honey Bee Brain upon Ontogenetic and Behavioral Development”

DOWNLOAD FULL TEXT ARTICLE: http://pubs.acs.org/stoken/presspac/presspac/full/10.1021/pr800823r

To avoid unwanted or unnecessary purchases, keep your hands off the goods. That’s the conclusion of a new study in the Journal of Consumer Research.

Authors Joann Peck (University of Wisconsin-Madison) and Suzanne B. Shu (UCLA) cite a 2003 warning from the Illinois state attorney general’s office that warned holiday shoppers to be cautious of retailers who encourage them to hold objects and imagine the objects as their own when shopping. The authors wondered whether the warning was valid and, more generally, if touch influences the feeling of ownership and valuation of an object.

“In our research, we have evidence that the warning from the attorney general is valid. In four studies, we find that merely touching an object increases the feelings of ownership a person has for the object. This, in turn, results in a person being willing to pay more for most objects that they touch versus objects that they cannot touch,” the authors write. “We also find that when touch is unavailable, such as shopping online, having people imagine owning a product increases their perception of ownership and how much they are willing to pay for a product.”

If people have a positive or neutral response to touching an object, they are willing to pay more for it, the authors explain. However, if an object does not feel particularly pleasant to the touch, it decreases the amount consumers are willing to pay. “For most products, the touch experience is positive or neutral so merely touching a product usually increases how much a person is willing to pay for an object,” the authors write.

The research may help explain the link between touch and impulse purchasing, the authors explain. “Encouraging touch in a retail store, as Apple does for products like the iPhone, may increase the feelings of perceived ownership and influence the amount a customer is willing to pay for a product.” Likewise, offers of “free trials” for a certain time before the consumer is obligated to pay are likely to increase perceived ownership and product valuation.

Encouraging ownership imagery can be an effective way for online retailers to increase sales, even when touch isn’t possible, the authors write. “Our findings that consumers respond effectively to the combination of no-touch and ownership imagery suggests a remarkable opportunity for online retailers to increase perceived ownership and purchase.”

Source: University of Chicago Press Journals

Consumers often make decisions by predicting how they’ll feel after an event or purchase. But different approaches to predicting lead to different conclusions, according to a new study in the Journal of Consumer Research.

Authors Jane E. J. Ebert (University of Minnesota), Daniel T. Gilbert (Harvard University), and Timothy D. Wilson (University of Virginia) examined the difference between two common ways of predicting emotions: forecasting and “backcasting.”

According to the authors, forecasters imagine how they’ll feel when an event occurs and then consider how they’ll feel subsequent to the event. In contrast, backcasters imagine their feelings in a future period and then consider the effects of an event. As an example, the authors give an example of a potential ad for a cruise. An ad that encouraged backcasting could read as follows: “How are you going to be feeling in frigid February? Imagine you take a sun-filled Caribbean cruise next week. Now imagine how you will feel in February. Help yourself through the winter…book a cruise today.”

The authors conducted several studies where they examined the thoughts of forecasters and backcasters and systematically varied the information available to participants. They discovered that when predicting their feelings for events, backcasters considered information about the event and the future time period more than the forecasters did. As a result, backcasters predicted more extreme feelings than forecasters did. Therefore, it would be beneficial for marketers to encourage backcasting in consumers.

“These differences in the information that backcasters and forecasters consider and in the predictions they make suggest that simply changing the order in which consumers think about a potential consumption event and an upcoming future time period can markedly change their expectations about their feelings following the event,” the researchers explain.

“Marketers should be able to change consumers’ expectations about their feelings simply by prompting them to think ahead to the future before considering a consumption event,” the authors conclude.

Source: University of Chicago Press Journals

EAST LANSING, Mich. – Using cell phones and playing video games may not be as harmful to children’s academic performance as previously believed, according to new research by a team of Michigan State University scholars.

In fact, cell phones had no effect on academic performance among a group of 12-year-olds, the researchers found in a three-year study published by the Conference Proceedings of the International Association for Development of the Information Society, or IADIS, in Barcelona, Spain.

And while the researchers found a strong relationship between video games and lower grade point averages, playing video games did not appear to affect math skills and had a positive relationship with visual-spatial skills. These skills – in which a child learns visually, by thinking in pictures and images – are considered the “training wheels” for performance in science, technology, engineering and math.

“And these are the areas where we want to see improvements in our children’s academic performance,” said lead investigator Linda Jackson, MSU professor of psychology.

The study is part of a larger MSU project, funded by the National Science Foundation, in which Jackson and colleagues are exploring the effects of technology on children’s academic performance and their social life, psychological well-being and moral reasoning.

The researchers surveyed students from 20 middle schools and an after-school center in Michigan. They asked how often the children used cell phones and played video games, both online and offline, and measured the children’s grades, visual-spatial skills and performance on standardized tests in math and reading.

As expected, females used cell phones more frequently than did males, while males played video games far more frequently than did females. Some 81 percent of adolescents play video games online, according to the Pew Internet and American Life Project.

Jackson said it’s unrealistic to think kids will stop playing video games, so video game developers should focus more on the elements that develop visual-spatial skills and less on themes such as violence. Also, more games should be developed that appeal to girls to better develop their visual-spatial skills, which are essential in professions such as surgery, she said.

“Girls are at a disadvantage by not having that three-dimensional experience,” Jackson said. “So when they get to medical school and they’re doing surgery in the virtual world, they’re not used to it.”

When it comes to cell phones, Jackson said she saw no detrimental effects to the students’ academic performance. However, further research is needed on older students who are more apt to engage in “devious behavior” such as text-messaging test answers to each other, she said.

The global cell-phone market had 1.8 billion subscribers in 2007 – a number that is expected to reach 3 billion by 2010, according to Baskerville Communications in London.

Source: Michigan State University

Of the six billion people sharing our planet, almost half live under the poverty line of $US2 per day. Though growth predictions vary it is likely that, by 2020, the population will increase by approximately another 1.2 billion, of which some 95% will live in developing countries. Such figures highlight the need to address the issues surrounding global poverty as a priority.

As part of the Economic and Social Research Council’s (ESRC) Global Financial Crisis lecture series, the second of three seminars looking at various aspects of the recession will focus on ‘Recession and Global Poverty’.

“How will the global financial crisis impact the extremely poor and extreme poverty?” asks Dr Peter Boone, of the ESRC’s Centre for Economic Performance. “Subsistence living and lack of accumulated wealth mean many of the extremely poor are well-insulated from the current crisis. However, the problems are in the future: reduced public finances, less global growth, less foreign aid, and possibly more civil wars, will mean the extremely poor do not get the health services, education and opportunities needed to pull themselves and their children out of poverty. This doesn’t have to be the case: despite all these problems, we have the knowledge and capacity to make large inroads towards ending extreme poverty.” Dr Boone will outline steps that the international community can take to ensure that we can lessen the impact of the crisis for the most vulnerable.

Professor of Economics, Tony Venables, of the University of Oxford, will discuss the impacts of the recession on developing countries, focusing his presentation on Africa. Africa has had strong economic growth for nearly a decade, but the latest forecasts have growth in 2009-10 dropping to around 3%, barely more than population increase. As a consequence tens of millions more people will remain in poverty and attainment of the MDGs made less likely. “Different economies are affected through quite different transmission mechanisms; drying up of capital flows; reduced export prospects; lower remittances; and lower commodity prices which affect some economies positively and others negatively.” explained Professor Venables. “The key question for the future is whether the recession is a one-off reduction in income and increase in poverty, or whether it will also reduce Africa’s growth prospects over coming decades, returning it the stagnation of the 1980s and 90s.”

Considering how the global financial crisis will exacerbate poverty for the most vulnerable households in developing countries will be Dr J Allister McGregor, Leader of the Vulnerability and Poverty Reduction Team at the Institute of Development Studies at the University of Sussex. Dr McGregor will also outline the potential outcomes of a failure by the global community to respond to the possible negative impacts of crisis on developing countries.

Source: Economic & Social Research Council

WASHINGTON – Romance does not have to fizzle out in long-term relationships and progress into a companionship/friendship-type love, a new study has found. Romantic love can last a lifetime and lead to happier, healthier relationships.

“Many believe that romantic love is the same as passionate love,” said lead researcher Bianca P. Acevedo, PhD, then at Stony Brook University (currently at University of California, Santa Barbara). “It isn’t. Romantic love has the intensity, engagement and sexual chemistry that passionate love has, minus the obsessive component. Passionate or obsessive love includes feelings of uncertainty and anxiety. This kind of love helps drive the shorter relationships but not the longer ones.”

These findings appear in the March issue of Review of General Psychology, published by the American Psychological Association.

Acevedo and co-researcher Arthur Aron, PhD, reviewed 25 studies with 6,070 individuals in short- and long-term relationships to find out whether romantic love is associated with more satisfaction. To determine this, they classified the relationships in each of the studies as romantic, passionate (romantic with obsession) or friendship-like love and categorized them as long- or short-term.

The researchers looked at 17 short-term relationship studies, which included 18- to 23-year-old college students who were single, dating or married, with the average relationship lasting less than four years. They also looked at 10 long-term relationship studies comprising middle-aged couples who were typically married 10 years or more. Two of the studies included both long- and short-term relationships in which it was possible to distinguish the two samples.

The review found that those who reported greater romantic love were more satisfied in both the short- and long-term relationships. Companion-like love was only moderately associated with satisfaction in both short- and long-term relationships. And those who reported greater passionate love in their relationships were more satisfied in the short term compared to the long term.

Couples who reported more satisfaction in their relationships also reported being happier and having higher self-esteem.

Feeling that a partner is “there for you” makes for a good relationship, Acevedo said, and facilitates feelings of romantic love. On the other hand, “feelings of insecurity are generally associated with lower satisfaction, and in some cases may spark conflict in the relationship. This can manifest into obsessive love,” she said.

This discovery may change people’s expectations of what they want in long-term relationships. According to the authors, companionship love, which is what many couples see as the natural progression of a successful relationship, may be an unnecessary compromise. “Couples should strive for love with all the trimmings,” Acevedo said. “And couples who’ve been together a long time and wish to get back their romantic edge should know it is an attainable goal that, like most good things in life, requires energy and devotion.”

Source: American Psychological Association